function AjaxRequest(){
	
	if(window.XMLHttpRequest){
		try{
			this.request = new XMLHttpRequest();
		}catch(e){
			this.request = null;
		}
	}else if(window.ActiveXObject){
		try{
			this.request = new ActiveXObject("Msxml2.XMLHTTP");
		}catch(e){
			try{
				this.request = new ActiveXObject("Microsoft.XMLHTTP");
			}catch(e){ 
				this.request = null;
			}
		}
	}
	if(this.request == null){
		alert("ajax error");
	}	
}

AjaxRequest.prototype.send = function(type,url,handler,postDataType,postData){
	if(this.request !=null){
		this.request.abort();
		url+="?dummy="+new  Date().getTime();
		
		try{
			this.request.onreadystatechange = handler;
			this.request.open(type, url, true);
			if(type.toLowerCase()=="get"){
				this.request.send(null);
			}else{
				this.request.setRequestHeader("Content-Type", postDataType);
				this.request.send(postData);
			}
		}catch(e){
			alert("ajax error send  server:"+e);
		}
	}
};
AjaxRequest.prototype.getReadyState = function() {
	  return this.request.readyState;
	};

	AjaxRequest.prototype.getStatus = function() {
	  return this.request.status;
	};

	AjaxRequest.prototype.getResponseText = function() {
	  return this.request.responseText;
	};

	AjaxRequest.prototype.getResponseXML = function() {
	  return this.request.responseXML;
	};

